Significance and changes of IGF-1 expression in brain and liver of rats with focal cerebral ischemia reperfusion injury

Objective To study the expression of insulin-like growth factor-1 (IGF-1) in brain and liver of rat with focal cerebral ischemia reperfusion injury. Methods The focal cerebral ischemia models were induced in rats by the filament method, and the expression of IGF-1 protein in brain and liver of rats was detected by the method of immunohistochemical staining 2h, 1,3,7d after reperfusion. Results The expression of IGF-1 was low in normal tissues of brain, while increased markedly 2h after reperfusion, peaked on day 3 after reperfusion, fell back on day 7.The expression of IGF-1 protein was mainly located in cerebral cortex after cerebral ischemia. ANOVA analysis revealed that there were significant differences in the number of IGF-1 positive cells between model group and sham-operation group at same time point (P 0.05). The difference of IGF-1 expression between different r perfusion time points in model group was significant (P 0.05). The expression of IGF-1 was very low in normal tissues of liver, and the number of IGF-1 positive cells in liver was not increased significantly at 2h and 1,3d after reperfusion in the model group as compared with that in the sham-operation group (P>0.05). But the number of IGF-1 positive cells in liver at 7d after reperfusion in the model group was increased significantly as compared with that in the sham-operation group and the other time points in model group (P<0.05). Conclusion There are obvious changes in IGF-1 expression in rat brain and liver after cerebral ischemia reperfusion, indicating that IGF-1 may play a role in cerebral ischemia reperfusion injury. Key words: Cerebral ischemia reperfusion;  Insulin-like growth factor I